Aloe vera is a tropical or subtropical plant of the genus aloe. The leaves, which are lance-shaped with sharp points, contain an essentially clear viscous gel. This gel has been used for centuries by those living where the plant grows for medical purposes such as an aid in the healing of wounds and relieving other skin irritations, including treatment of minor burns.
Experience has demonstrated that maintaining the therapeutic qualities of the gel of the aloe vera plant requires that steps be taken to protect the gel from deteriorating. Typical of these protective processes is the addition of antioxidants as disclosed by U.S. Pat. No. 3,892,853. This patent, for example, describes the usefulness of the aloe gel in treating a jellyfish sting by stating that relief is total if fresh gel is used, but that if the gel is more than one and a half hours old, the gel is totally ineffective for this purpose. The reference, however, states further that fever blisters have been successfully treated with gel three weeks after extraction from the aloe vera plant, but not with gel as old as three months. Thus for some uses, freshness does not appear to be very important. However, these discussions clearly demonstrate that if the ointment is to be used in a wide range of applications, some method of protecting the freshness is required.
Aloe vera has also been used in cosmetic mixtures, as illustrated in U.S. Pat. No. 4,369,180. In this patent, the aloe vera was mixed with a wide variety of ingredients including mixtures of vitamins A, D, and E. All of these applications of the aloe vera plant either required complex processing for preparing the mixture, a wide variety of additive ingredients, or both.
The necessity for some method of protecting the gel is further described in U.S. Pat. No. 3,892,853. This patent states that at room temperature, the unprotected gel becomes rancid within twenty-four hours. In an inert atmosphere, it may remain fresh as long as five weeks. Under refrigeration, it may remain fresh only as long as six weeks.